mainlining shenanigans
c1d2c7d47e
cr=0 is supposed to be an optimization to save CPU cycles, but if buddy data (in memory) is not initialized then all this makes no sense as we have to do sync IO taking a lot of cycles. Also, at cr=0 mballoc doesn't choose any available chunk. cr=1 also skips groups using heuristic based on avg. fragment size. It's more useful to skip such groups and switch to cr=2 where groups will be scanned for available chunks. However, we always read the first block group in a flex_bg so metadata blocks will get read into the first flex_bg if possible. Using sparse image and dm-slow virtual device of 120TB was simulated, then the image was formatted and filled using debugfs to mark ~85% of available space as busy. mount process w/o the patch couldn't complete in half an hour (according to vmstat it would take ~10-11 hours). With the patch applied mount took ~20 seconds. Lustre-bug-id: https://jira.whamcloud.com/browse/LU-12988 Signed-off-by: Alex Zhuravlev <azhuravlev@whamcloud.com> Reviewed-by: Andreas Dilger <adilger@whamcloud.com> Reviewed-by: Artem Blagodarenko <artem.blagodarenko@gmail.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.